Serotonin (5-HT) and Dopamine recognize several well-defined cell surface receptors. Among these, 5-HT.sub.1A, 5-HT.sub.2A, and D.sub.4 at which serotonin and dopamine, respectively, have high affinity, are known to be implicated in many Central Nervous System (CNS) disorders such as depression, anxiety, schizophrenia, Parkinson's disease, and neurodegenerative diseases.
In the previous art, several classes of compounds able to interfere with the neurotransmission at serotonin or dopamine receptor subtypes are known. Particularly, derivatives based on the core structure of the arylpiperazine and benzimidazolone have been described (e.g., GB 2,023,594; U.S. Pat. No. 3,472,854; U.S. Pat. No. 4,954,503; and WO 98/33784), and targeted both to generic serotonin or dopamine receptors and to a specific receptor subtype. In another patent (U.S. Pat. No. 5,576,318), compounds based both on the benzimidazolone and phenyl piperazine structures are described: in this latter case the described affinities are limited to 5-HT.sub.1A and 5-HT.sub.2A receptor subtypes.